(roo´bin-stīn) Rubinstein-Taybi syndrome a congenital condition characterized by mental and motor retardation, broad thumbs and great toes, short stature, characteristic facies including high-arched palate and straight or beaked nose, various eye abnormalities, pulmonary stenosis, keloid formation in surgical scars, large foramen magnum, and abnormalities of the vertebrae and sternum.